Near-field and Far-field Properties of Gold Spiky Nanoparticle Dimers

Strong electric fields play a vital role in surface-enhanced spectroscopy, localized surface plasmon resonance sensing, and photothermal therapy. Nanoparticle dimers and spiky structures are the two kinds of structures that can provide intense electric fields. Combining the benefits of both narrow gaps and spiky structure, spiky nanoparticle dimers (SNDs) are anticipated to provide further enhanced electric fields. Using finite-difference time-domain method, the near-field and far-field properties of SNDs with different configurations are numerically investigated. Meanwhile, SNDs with which kind of configuration exhibit high performance in plasmonic applications are determined. The results demonstrate that SNDs with tip to tip and tip to sphere configurations exhibit highly tunable resonance positions, intense electric fields, and large "hot spots volumes", indicating their great potentials for plasmonic applications.